Amprenavir is a protease inhibitor used to treat HIV infection.
Indication
For the treatment of HIV-1 infection in combination with other antiretroviral agents.
Pharmacology
Amprenavir is a protease inhibitor with activity against Human Immunodeficiency Virus Type 1 (HIV-1). Protease inhibitors block the part of HIV called protease. HIV-1 protease is an enzyme required for the proteolytic cleavage of the viral polyprotein precursors into the individual functional proteins found in infectious HIV-1. Amprenavir binds to the protease active site and inhibits the activity of the enzyme. This inhibition prevents cleavage of the viral polyproteins resulting in the formation of immature non-infectious viral particles. Protease inhibitors are almost always used in combination with at least two other anti-HIV drugs.
Affected Organisms
Human Immunodeficiency Virus
Biotransformation
Hepatic. Amprenavir is metabolized in the liver by the cytochrome P450 3A4 (CYP3A4) enzyme system. The 2 major metabolites result from oxidation of the tetrahydrofuran and aniline moieties. Glucuronide conjugates of oxidized metabolites have been identified as minor metabolites in urine and feces.
Absorption
Rapidly absorbed after oral administration in HIV-1-infected patients with a time to peak concentration (Tmax) typically between 1 and 2 hours after a single oral dose. The absolute oral bioavailability of amprenavir in humans has not been established.
Half Life
7.1-10.6 hours
Protein Binding
Very high (90%). Amprenavir has the highest affinity for alpha(1)-acid glycoprotein.
